CSV vs Excel: what is the difference?

CSV is plain text any program can read; an Excel file holds formulas, formatting and types. When to use each and how to convert without damaging data.

Last updated September 21, 2026

The two formats look the same when Excel opens them, which is why they get confused. They’re built for different jobs and using the wrong one is behind a lot of lost formatting, broken imports and quietly damaged data.

CSV: plain text, one table

A CSV file is text. Each line is a row and commas separate the values:

name,zip,amount
Ada,02134,19.99

That is all it can hold: no formulas, no formatting, no second sheet and no way to say what kind of value something is. Its strength is that every program can read it, which makes it the standard for moving data between systems.

Excel: a workbook

An .xlsx file is a structured package holding several sheets, formulas, formatting, charts and a type for every cell. It is built for working with data, not for moving it. Other software can read it, but less universally than CSV.

Choosing

• Sending data to another system (a mailing tool, a database, accounting software): CSV.
• Sending data to a person to read or work on: Excel, so it opens with nothing changed.
• Keeping your own working file: Excel, so formulas and formatting survive.

Converting without damage

Going from CSV to Excel is where things break. Excel guesses the type of every CSV value as it opens, dropping leading zeros and rounding long numbers, as covered in why Excel removes leading zeros. CSV to Excel avoids that by writing a real workbook where each value is typed explicitly and several CSVs can become several sheets.

Going from Excel to CSV is simpler but loses everything except values. Excel to CSV gives you each sheet as a CSV, including from old .xls files, which are covered in how to open an .xls file without Excel.

Semicolons and tabs

In much of Europe, Excel writes CSV with semicolons, because the comma is the decimal separator. Tab-separated files are another variant. Good tools detect the separator automatically; if yours shows everything in one column, the separator is the reason.